JP6413062B2 - How to design sunglasses lenses for people who do not need myopia correction - Google Patents

Description

  The present invention relates to a method for designing a lens for sunglasses that is worn by a person with visual acuity who does not need to correct myopia with glasses or contact lenses in normal life.

Sunglasses are worn fashionably or to protect your eyes from UV rays during the day. In the past, there were many lenses with a very low visible light transmittance, for example, a visible light transmittance of 50% or less. Recently, however, the visible light transmittance is about 80%, such as a slightly colored transparent lens. Some sunglasses use lenses. Various types of sunglasses have been proposed, such as those that are listed on the glasses with lenses fitted to the frame, those that are attached to the glasses that are worn with clips, and those that are ski goggles. Patent document 1 is shown as an example of the lens for sunglasses.
When wearing sunglasses, if a person who needs to correct myopia with glasses or contact lenses in normal life wears sunglasses without using glasses or contact lenses to correct them, the lens for the sunglasses It is necessary to set the lens power (S power or C power) according to the visual acuity of the person. On the other hand, if the person does not particularly need myopia correction in normal life, the lens power is not set for the lens for sunglasses. In other words, in this case, the lens should have no vision correction function in which only the transmittance of the lens is set low.

Registered Utility Model No. 3004262

However, even a person who does not particularly need myopia correction in normal life, there is a potential myopic person who actually becomes difficult to see the surrounding scenery when dark. This is because the amount of light entering the eye by darkening, that is, visual information decreases, so the refractive power adjustment of the eye becomes inaccurate, or the pupil enlarges by darkening, and the spherical aberration of the crystalline lens appears. It is thought to be caused by factors such as becoming easier.
Therefore, when wearing sunglasses for such a potential myopic person, it is necessary to measure the visual acuity of the person in a dark place and use a sunglasses with a corrected lens power. However, it is actually bothersome that people who have not corrected myopia even in normal life dare to measure their visual acuity when wearing their own sunglasses just to wear sunglasses and correct accordingly. There is nothing. For this reason, it has been necessary to use sunglasses with lenses that have not been corrected for myopia even in the case of a potential myopic person who has difficulty in seeing the surrounding scenery when dark.
The present invention has been made paying attention to such problems existing in the prior art. The object is to provide a lens design method for sunglasses that is particularly advantageous for people with potential myopia, when darkness makes it difficult to see the surrounding scenery.

  In order to solve the above problems, as a first means, it is not necessary to correct myopia in normal life, and at least the refraction value is not positive in the scotopic vision, but the refraction value in the scotopic vision is not refracted in the photopic vision. This is a lens design method for sunglasses for people who have a negative value after subtracting the value, and only S power is set to the lens in the range of -0.75 diopter to 0 diopter, and C power is not set. The gist is to make it.

According to the above means, people who become difficult to see the surrounding scenery when dark when they do not require myopia correction, do not feel overcorrection and correct when using sunglasses with such a design. Compared to the case of not doing, the focus will be fixed and the scenery will not be blurred. In a lens with a transmittance range that can be generally used as sunglasses for people who do not need myopia correction and the surrounding scenery becomes difficult to see when dark, the preferred myopia correction power is -0.75 diopter than S The frequency is rarely reduced. In addition, by not setting the C power, a lens with a power suitable for use as a sunglasses lens for a person who does not need most myopia correction without designing various types of myopia corrected lenses. It becomes possible to provide. In addition, even a person having only a negative C power can correct myopia by wearing such a lens.
In this lens, the refractive value of the eye (S frequency + (C frequency / 2)) in a dark place is not positive, and the value obtained by subtracting the refractive value in photopic vision from the refractive value in dark vision is negative. Applies to some people.
In the above description, “−0.75 diopter to 0 diopter” is a concept including both −0.75 diopter and ± 0 diopter (that is, “to” includes numerical values at both ends thereof). The lens is intended for a single focal point.
In the present invention, “does not require myopia correction in normal life” means that myopia is not corrected with glasses or contact lenses on a daily basis.
Note that myopia is when the S power is negative in the refractive power of the person, and is calculated as the reciprocal of the distance (cm) from the farthest object that is clearly visible to the eye divided by 100. This unit is called diopter. Correcting myopia with a lens means that the lens is put into a normal vision state where the S frequency is 0 diopter (approaching it). A person who has not corrected his or her visual acuity with glasses or contact lenses does not necessarily have a visual acuity of ± 0 diopter. In general, correction of visual acuity is not necessary if it is about -0.5 to +0.5 diopter.

The gist of the second means is that the S frequency is set between -0.50 and -0.25 diopters.
As a suitable myopia correction, the S frequency does not become smaller than −0.75 diopter, but this range is particularly suitable for a person who does not need more myopia correction.
The gist of the third means is that the S frequency is set to -0.25 diopter. This setting is suitable for a person who does not need more myopia correction. This is particularly good when the transmittance of the lens is high.
The gist of the fourth means is that, as the transmittance of the lens for sunglasses is higher, a higher S frequency is set within a range of -0.75 diopter to 0 diopter.
In other words, a higher S power in the range of -0.75 diopters to 0 diopter when the transmittance of the lens by darkening lenses for sunglasses as low Ku becomes, the color of less lens conversely The setting is such that the S frequency decreases in the range of -0.75 diopter to 0 diopter as the lens is closer to a darker and not ordinary color lens. This is because the darker the color of the lens, the greater the tendency for the surrounding scenery to become difficult to see when it becomes dark, even though myopia correction is not required.

  ADVANTAGE OF THE INVENTION According to this invention, the lens for sunglasses which is especially advantageous in the person of the potential myopia that it becomes difficult to see the surrounding scenery when it becomes dark can be provided.

A scatter diagram in which the horizontal axis represents the refraction value at 3 mm pupil and the vertical axis represents the refraction value at 5 mm pupil minus the refraction value at 3 mm pupil.

Hereinafter, the present invention will be described in detail based on the results of analyzing photopic vision and scotopic vision of a person who has not corrected visual acuity with glasses or contact lenses.
(1) Differences in pupil size between photopic and dark vision The size of the pupil diameter when wearing sunglasses and when not wearing sunglasses is verified, and changes in pupil diameter are observed in bright and dark places. This is to determine what kind of causal relationship exists in the difference in visibility.
The transmittance of an image of a very dark night after 18 subjects who have not corrected their vision with glasses or contact lenses, after illuminating at 170 lux and performing a normal refraction test in photopic vision. A refraction test was performed again with wearing sunglasses with a very low lens (luminous transmittance 6%). The results are shown in Table 1. As a result, it was 3.6 mm in photopic vision and enlarged to 5.8 mm in dark vision. The enlargement ratio was 164%. This dark-sighted condition is actually a case where it is too dark to be used as a lens for ordinary sunglasses. In addition, the maximum pupil diameter (under conditions such as night without the moon) of ordinary Japanese is about 7 mm.

(2) Change of subjective refraction value accompanying pupil change The wearer's subjective visibility was verified when wearing the sunglasses of the above lens. In other words, we examined the percentage of people who became difficult to see the surrounding scenery when dark, and what kind of refractive anomalies they developed.
For 42 subjects who have not corrected their visual acuity with glasses or contact lenses, a subjective comparison is made with the S frequency when not wearing sunglasses (the appearance of photopic vision in (1) above). It was performed together with the measurement. The S frequency was measured using a trial lens for each person in the above-mentioned photopic and scotopic states, and the difference was obtained by subtracting the S frequency of photopic vision from the S frequency of scotopic vision. . As a result, as shown in Table 2, there were 18 “groups that were difficult to see at night” and 24 “groups that were difficult to see at night”. And when the average of the difference of S frequency was calculated | required about each group, it was -0.31 diopter in the former, and -0.08 diopter in the latter. From this result, it is considered that a person who feels difficult to see at night develops a refractive error of myopia as the pupil becomes larger. However, since the average value is calculated here, the degree of variation in the degree of myopia is not well understood.

(3) Change in objective refraction value associated with pupil change In the above (2), it was verified whether or not it was subjectively difficult to see. However, it is not clear what the difference in refractive values of the eyes is between objective (ie objective) and photopic and scotopic visions. In addition, it is difficult to understand how much S power should be set for the lens for sunglasses only with the average value as described above. Therefore, the inventor used the refractive power analyzer (made by NIDEK: OPD-scanII) for 36 subjects who have not corrected their visual acuity with eyeglasses or contact lenses. (S frequency + (C frequency / 2)) was measured, a scatter diagram as shown in FIG. 1 was created, and this was verified. Although it performed about each right and left eye, the data of the left eye are shown here.
In FIG. 1, the horizontal axis (x axis) represents the refraction value at 3 mm pupil (S frequency + (C frequency / 2)), and the vertical axis (y axis) represents the refraction value at 3 mm pupil from the refraction value at 5 mm pupil. It is a scatter diagram with the value subtracted (unit is diopter). Analyzing this figure, it can be said that the number of subjects belonging to the third quadrant (both x and y coordinates are negative) is the most, and it is objectively difficult to see in the dark. In the second quadrant and the fourth quadrant, dark vision is more like normal vision, so sunglasses that correct myopia are unnecessary for these subjects. The first quadrant is considered a unique case.

Therefore, now, looking at the vertical axis (y-axis) of the third quadrant, the refraction values to be corrected are between -0.75 diopter and 0 diopter. From this result, it can be determined that the S power given to the lens for sunglasses for people who are difficult to see the surrounding scenery when dark is set to -0.75 diopter to 0 diopter. In particular, it should be between -0.5 and 0.25 diopters.
However, this result is a refraction value and includes the C frequency in the numerical value. Therefore, based on this result, whether or not it should be reflected as it is as a single value of S power as it is, that is, of a lens that gave only such a weak S power to a person having only a negative C power in scotopic vision. To verify whether myopia is improved by wearing sunglasses. Assume that there is a subject of S ± 0, C −0.0 in photopic vision and S ± 0, C −0.5 in scotopic vision (hereinafter referred to as subject A). The refraction value of the subject A is −0.25, and is included in the third quadrant. Assume that the subject A wears a lens having a power of S-0.25 as a lens for sunglasses. As a result, S + 0.25 and C ± 0 are obtained in the dark place, and although the S frequency is displaced in the positive direction, the C frequency which is 0.5 in absolute value is reduced, so that the overall appearance is improved. The Rukoto. Therefore, from the result of FIG. 1, it is appropriate to set the lens for sunglasses of a person included in the third quadrant in terms of refraction to −0.75 diopter to 0 diopter as S power.
Even when an actual sunglasses lens is worn, a 5 mm pupil is rare. Because the light reaches the pupil indirectly from around the sunglasses, it is actually too dark to maintain the pupil smaller than the 5mm pupil even if the lens for sunglasses has a very small transmittance that is not practical. . Therefore, there is no possibility that the sample will be at a position of −0.75 diopter or less in the third quadrant.

Claims (3)

For those who do not require myopia correction in normal life and at least the refraction value is not positive in scotopic vision, but the value obtained by subtracting the refraction value in photopic vision from the refractory value in scotopic vision is negative A method for designing a lens for sunglasses,
In the range of −0.75 diopter to 0 diopter, only the S power is set to the lens, and the C power is not set, and the transmittance of the lens for the sunglasses in the range of −0.75 diopter to 0 diopter is set. The design method of the lens for sunglasses for the person who does not require myopia correction characterized by setting higher S frequency, so that is high .   2. The method for designing a lens for sunglasses according to claim 1, wherein the S frequency is set between -0.50 and -0.25 diopters.   2. The method for designing a lens for sunglasses according to claim 1, wherein the S frequency is set to -0.25 diopter.

Images